Here is the log file of roslaunch
It may be useful
[roslaunch][INFO] 2014-01-27 12:44:10,671: Checking log directory for disk usage. This may take awhile. Press Ctrl-C to interrupt
[roslaunch][INFO] 2014-01-27 12:44:16,141: master.isrunning[http://localhost:11311]
[roslaunch][INFO] 2014-01-27 12:44:16,243: master.isrunning[http://localhost:11311]
[roslaunch][INFO] 2014-01-27 12:44:16,343: master.isrunning[http://localhost:11311]
[roslaunch][INFO] 2014-01-27 12:44:16,347: master.isrunning[http://localhost:11311]
[roslaunch][INFO] 2014-01-27 12:44:16,349: ROSMASTERURI=http://localhost:11311
[roslaunch][INFO] 2014-01-27 12:44:16,351: setting /runid to 562a6bf0-8748-11e3-b40d-8ca9821c9902 [roslaunch][INFO] 2014-01-27 12:44:16,354: setting /roslaunch/uris/hostmagoxpsl501x_54926' to http://mago-XPS-L501X:54926/
[roslaunch][INFO] 2014-01-27 12:44:16,358: ... preparing to launch node of type [rosout/rosout]
[roslaunch][INFO] 2014-01-27 12:44:16,450: ... successfully launched [rosout-1]
[roslaunch][INFO] 2014-01-27 12:44:16,450: loadparameters starting ...
[roslaunch][INFO] 2014-01-27 12:44:16,455: ... loadparameters complete
[roslaunch][INFO] 2014-01-27 12:44:16,455: launchnodes: launching local nodes ...
[roslaunch][INFO] 2014-01-27 12:44:16,455: ... preparing to launch node of type [gazeboros/gzserver]
[roslaunch][INFO] 2014-01-27 12:44:16,455: createnodeprocess: package[gazeboros] type[gzserver] machine[Machine(name[] envloader[None] address[localhost] sshport[22] user[None] assignable[True] timeout[10.0])] masteruri[http://localhost:11311]
[roslaunch][INFO] 2014-01-27 12:44:16,512: ... created process [gazebo-2]
[roslaunch.pmon][INFO] 2014-01-27 12:44:16,512: ProcessMonitor.register[gazebo-2]
[roslaunch.pmon][INFO] 2014-01-27 12:44:16,512: ProcessMonitor.register[gazebo-2] complete [roslaunch][INFO] 2014-01-27 12:44:16,512: ... registered process [gazebo-2]
[roslaunch][INFO] 2014-01-27 12:44:16,528: ... successfully launched [gazebo-2]
[roslaunch][INFO] 2014-01-27 12:44:16,528: ... preparing to launch node of type [gazeboros/gzclient]
[roslaunch][INFO] 2014-01-27 12:44:16,594: ... created process [gazebogui-3]
[roslaunch.pmon][INFO] 2014-01-27 12:44:16,594: ProcessMonitor.register[gazebogui-3] [roslaunch.pmon][INFO] 2014-01-27 12:44:16,594: ProcessMonitor.register[gazebogui-3] complete [roslaunch][INFO] 2014-01-27 12:44:16,594: ... registered process [gazebogui-3]
[roslaunch][INFO] 2014-01-27 12:44:16,639: ... preparing to launch node of type [gazeboros/spawnmodel]
[roslaunch.pmon][INFO] 2014-01-27 12:44:16,711: registrations completed <processmonitor(processmonitor-1, started="" daemon="" 140345190778624)>="" [roslaunch.parent][info]="" 2014-01-27="" 12:44:16,711:="" ...="" roslaunch="" parent="" running,="" waiting="" for="" process="" exit="" [roslaunch][info]="" 2014-01-27="" 12:44:16,712:="" spin="" [="" roslaunch][error]="" 2014-01-27="" 12:44:20,824:="" [gazebo-2]="" process="" has="" died="" [pid="" 2899,="" exit="" code="" 127,="" cmd="" opt="" ros="" hydro="" lib="" gazebo<em="">ros/gzserver /home/mago/Development/Repository/ROS/labrobhydrohetcont/src/ugvgazebo/worlds/ugv.world
_name:=gazebo _log:=/home/mago/.ros/log/562a6bf0-8748-11e3-b40d-8ca9821c9902/gazebo-2.log]. log file: /home/mago/.ros/log/562a6bf0-8748-11e3-b40d-8ca9821c9902/gazebo-2*.log [roslaunch.pmon][INFO] 2014-01-27 12:44:20,824: ProcessMonitor.unregister[gazebo-2] starting [roslaunch.pmon][INFO] 2014-01-27 12:44:20,824: ProcessMonitor.unregister[gazebo-2] complete [roslaunch.pmon][INFO] 2014-01-27 12:44:46 ... (more)
What version of ros-gazebo-pkgs and gazebo are you using? Are you only using the ROS repository or you are also using packages.osrfoundation.org?